These Forgefix extra large Clout Nails have a larger head, which distributes the load directly underneath the top of the nail, ensuring that roofing felt stays firm and secure. This reduces the risk of tearing. The nails are galvanised for increased resistance to corrosion. Suitable for roofing of all types. APPLICATION: Specifically used when roofing felt is being fitted to either shed or similar types of roofs. Galvanisation is a process of applying a protective zinc coating to steel in order to prevent rusting. Zinc coatings prevent corrosion of the protected metal by forming a physical barrier, and by acting as a sacrificial anode even if this barrier is damaged.